The incorporation of rare earth ions of lanthanide series of elements with numbers ranging from 57 to 71 of the Mendeleev's periodic system in glasses has led to the development of optical fiber lasers and amplifiers. Current interest is directed towards erbium-doped fibers for the fabrication of optical fiber amplifiers at 1.5 .mu.m signal wavelength. These fiber amplifiers are typically doped with Er at a concentration of 10-100 ppm. For the principle of fabrication and operation of such an amplifier see W. J. Miniscalco, "Erbium-Doped Glasses for Fiber Amplifiers at 1500 nm", Journal of Lightwave Technology, Volume 9, No. 2, Feb. 2, 1991, pp. 234-249. Recently it was established by A. Polman et al., that planar waveguides and amplifiers could be formed by implanting Er into thin SiO.sub.2 films at concentrations of 10.sup.2 -10.sup.4 ppm. The guides were typically 2 .mu.m thick, 5 .mu.m wide and 5 cm long. See A. Polman et al., "Optical Doping of Waveguide Materials by Me V Er Implantation", Journal of Applied Physics, Vol. 70, No. 7, Oct. 1, 1991, pp. 3778-3784, and U.S. Pat. No. 5,039,190 issued to A. Polman et al., on Aug. 13, 1991, which are incorporated herein by reference. A. Polman et al. demonstrated that Er can be incorporated in thin films of transparent waveguide materials using MeV implantation. Implantation doping of, for example, SiO.sub.2, phosphosilicate glass, and Si.sub.3 N.sub.4 with Erbium ion by Polman et al., in films of transparent waveguide materials using MeV implantation resulted in sharply peaked photoluminescence spectra centered around 1.5 .mu.m with lifetimes up to 15 ms. The operation of optical amplifiers depends on stimulated emission from the 1.5 .mu.m excited state of Er, and the efficiency of amplification will depend upon the lifetime of spontaneous emission rate from that level.
Besides planar waveguide lasers and optical amplifiers, there is a potential interest for planar light-emitting devices which do not rely on an optical gain, or stimulated emission, principle. Erbium as the active element would be the most promising choice for devices operating in the 1.5 .mu.m region because of its 1.5 .mu.m optical transition between intra-4f electronic states, which are only slightly perturbed by the surrounding host. Although non-planar 1.5 .mu.m light-emitting devices, such as optical fiber lasers, can advantageously be used in a variety of communications systems, there are many potential applications for light-emitting devices for which non-planar devices are not readily or conveniently adapted. For instance, it would be desirable to integrate a light-emitting device with electronic and opto-electronic devices or structures, since such integration is expected to result in decreased cost, increased ruggedness and possibly greater speed. Such integration would be facilitated by the availability of an efficient planar 1.5 .mu.m light-emitting device. Furthermore, the availability of such devices would significantly advance progress toward fully integrated optics; these devices can be expected to be desirable replacements for non-planar devices, due to their more compact nature and increased mechanical stability, and are likely to find an application in lightwave communications systems.